Ultrasound

The Basics

An ultrasound is a non-invasive exam that creates images of structures inside the body. It uses high-frequency sound waves that reflect off body tissues. These waves are received and converted to real-time images on a computer screen by a handheld device called a transducer.

Ultrasounds are useful in diagnosing and treating many conditions. Your doctor will determine when an ultrasound is needed. This test is commonly used for the following:

examining body organs for tumors or abnormalities

assisting in procedures such as biopsies

assessing blood flow through blood vessels

examining the growth of a fetus during pregnancy

determining causes of infection

Risks and precautions

An ultrasound is usually a straightforward and safe procedure. Unlike other imaging tests, ultrasound uses low-energy sound waves that are not associated with any notable risks.

Before the test

You may not need to prepare for some types of ultrasounds. For others, you may have to abstain from eating or drinking before the test, or you may be instructed to drink a large amount of water so that your bladder is full. Follow the instructions given to you by your doctor.

If you are taking any prescription or over-the-counter (non-prescription) medications, supplements, or herbal products, make sure you inform your doctor or pharmacist. Ask them whether it is necessary for you to stop taking any of these medications and products before the test. It is also important to tell them if you have allergies to certain medications or have certain medical conditions.

The contents of this health site are for informational purposes only. Always seek the advice of your physician or other qualified healthcare provider regarding any questions you may have about a medical condition.